Communication networks are widely used today; the variety of networks includes the Internet, wide-area networks (WANs), local-area networks (LANs), telephony networks, and wireless networks. The importance of network monitoring and testing is growing as well as the requirements for the related methods and equipment.
Monitoring devices may be implemented within the network for monitoring communication along such network. Such monitoring devices are referred to as “eavesdropping devices” or “passive probes;” they are generally not a party to the communication but instead are monitoring such communication, e.g. for performance monitoring, testing, or other reasons. The elements that constitute the network may also act as eavesdropping devices because they may take traffic traveling through the device and replicate it on another egress port for use by monitoring or testing devices.
A test device for analyzing traffic packets may be attached directly to a monitor port or passive network tap at a switch or element.
Conventionally, a device in a network requires an IP address to communicate with it over an IP routed network. If a device doesn't have an IP address, it can only be communicated with on the local subnet by utilizing MAC level protocols. Some devices, like intelligent network taps, passively tap a network to provide access to the packets and therefore require an IP address and often a separate management network connection. There are disadvantages to having IP addresses on large numbers of devices and separate management networks due to cost and scalability. In order to minimize the total number of IP addresses required on a network, certain devices such as test devices may be not assigned a unique IP address.
Once installed and properly configured, a system of such test devices may be successfully controlled by a control device. However, the initial deployment of the system presents a challenge of mapping test devices relative to the communication network wherein the test devices are installed; especially if information about the underlying network is not sufficient and also needs to be discovered. For a handful of test devices, a technician can provide information e.g. though a command line. Monitoring of large networks requires a large number of test devices, and discovering multiple, possibly unaddressed devices and mapping such a test system relatively to the network being monitored, is more difficult.
Collecting information about test devices and their positions in the network may be complicated by the presence of aggregated link groups (LAG) within the network. The network may include LAG devices from a variety of vendors. In addition, different customers may configure their LAGs differently. By way of example, various parameters such as source/destination IP addresses or virtual local area network (VLAN) IDs may be used as hash keys for load balancing. Additionally, parts of the network may perform load rebalancing, which further complicates collection of information about the test devices, as well as communication between the central control device and the test devices. The dynamic load balancing may result in that some test devices may be “lost” and rediscovery may be required.
It would therefore be useful to provide an improved method of collecting information about test devices connected in a network.